Surprise that NZ hasn't acted earlier on foreign influence

New Zealand's being warned it needs to crack down on foreign political interference like Australia. Across the Tasman, the government is planning to ban foreign political donations, the legal definition of espionage is being changed and a register introduced for foreign lobbyists. Prime Minister Malcolm Turnbull says Australia cannot afford to be naive about the threat of foreign interference. Canberra Professor in public ethics Clive Hamilton joins us to discuss the issue.